Alabama Soil and Water Blog Spot

  Alabama’s new 2022 Blue Book contains some changes related to silt fences.  One change is that the silt fence should be designed for dewatering and potential overtopping. The silt fence at full capacity should dewater in 4 to 12 hours. An overflow should be included that conveys the peak discharge for the design event.  While there can be several methods to meet these requirements, one is shown in the picture by inserting an overflow and dewatering board at the lowest point in the fence.   Also, remember that a silt fence should pond the runoff water from its small watershed for the design storm event.   Perry L Oakes, PE Erosion and Sediment Control Program Coordinator AL Soil and Water Conservation Committee

  When establishing vegetation it is always best to do so with conventional methods like discing, incorporation of soil amendments, seeding and mulching. However, slopes steeper than 3H:1V  are often shaped by dozer, topsoil spread by dozer, and a hydroseeding machine used to spread amendments, seed, and mulch.  In situations like this, always remember to “ track “ the slope prior to hydroseeding.   Perry L Oakes, PE Erosion and Sediment Control Program Coordinator AL Soil and Water Conservation Committee

  This picture shows what could have been an effort to save a couple of trees on a construction site.  However, the trees didn’t survive.   Roots require oxygen that comes from the soil surface.  Anything done to the soil surface to minimize or eliminate the oxygen transfer will probably kill the tree.   I always encourage planners and designers to preserve trees on the site to be developed.  To safeguard the trees, you must: Mark off the area around the tree at least to the drip line, or better yet, well beyond the drip line. Keep ALL heavy equipment off this protected area. This means there probably needs to be hand-clearing in the area. DO NOT place soil on top of the rooted (protected) area. DO NOT place soil against the tree. DO NOT place or store chemicals or fuels within the root (protected) area. If trenching through the protected area is required, do not cut the roots in the trench. Professionals know how to do this with

  We need heavy equipment in order to construct and especially to move and shape soil on our projects.  We have often seen in construction specifications that equipment should be properly maintained and free of leaks.  This is especially true when working around water.  I’m not sure how long it takes for soil to recover when a petroleum type spill occurs, but I do know that the bare spot in this picture had a hydraulic fluid spill 5 years ago.  Accidents happen, but preventive maintenance can prevent some from occurring.   Perry L Oakes, PE Erosion and Sediment Control Program Coordinator AL Soil and Water Conservation Committee

  This  is a continuation of Erosion and Sediment Control Tip #45 in the “Did You Know” category.   It is unfortunate that enforcement is needed in Alabama to make people comply with the basics of the general permit.  As you know, when any portion of the site is complete, the permittee must begin the implementation of final stabilization before the end of the next business day following the day when the construction activities have temporarily or permanently ceased.   Tip provided by: J. Steve Newton, P.E. Senior Project Manager TTL Inc.  

  This is a picture of what a site should look like where erosion and sediment control are a priority.   I recently read an article about a construction site that was just finalized.  The author was excited that the job was completed and one statement caught my eye.    “All the vegetation work was completed on the final day of the project.”   The only question I ask is, WHY?  Surely some of the vegetation could have been completed as areas within the project were finished.  Remember, it’s not “business as usual” anymore.  Exposed soil should be covered with vegetation or landscaping at every opportunity and NOT the LAST opportunity. Leaving areas bare over long periods of time exposes the soil surface to erosion.     Mark your Calendar.  Clear Water Alabama will be September 20-21, 2023, in NW Alabama.   Perry L Oakes, PE Erosion and Sediment Control Program Coordinator AL Soil and Water Conservation Committee